Apparatus for converting a stack of sheets into a stream of overlapped sheets

ABSTRACT

A first conveyor conveys a stack of sheets which stand on edge. A second conveyor is located at a level above the path in which the stack advances. A third conveyor extends substantially vertically across the path to pick up the respectively leading sheets of the stack and convey them in upward direction. A presser belt cooperates with the third conveyor to engage the pick-up sheets and convey to the second conveyor on which they are deposited so that each sheet partially overlaps a preceding sheet.

[ July 15, 1975 United States Patent [1 1 Miiller 1 APPARATUS FOR CONVERTING A STACK OF SHEETS INTO A STREAM OF OVERLAPPED SHEETS 1/1972 Stbb............... 6/1973 FOREIGN PATENTS OR APPLICATIONS [75] Inventor: Hans Miiller, Zofingen, Switzerland [73] Grapha-Holding AG, Hergiswil,

Switzerland 477,347 /1969 Swit1erland.........i................ 271/34 Assignee:

[22] Filed: Sept. 13, 1973 Primary ExaminerRichard A. Schacher Assistant Examiner-Bruce H. Stoner, Jr.

[2]] Appl' No; 397094 Attorney. Agent. or FirmMichael S. Striker [57] ABSTRACT A first conveyor conveys a stack of sheets which stand on edge. A second conveyor is located at a level above Foreign Application Priority Data Sept. 21, 1972 Switzerland......................

the path in which the stack advances. A third conveyor extends substantially vertically across the path to pick up the respectively leading sheets of the stack and convey them in upward direction. A presser belt cooperates with the third conveyor to engage the pickup sheets and convey to the second conveyor on which they are deposited so that each sheet partially overlaps a preceding sheet.

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APPARATUS FOR CONVERTING A STACK OF SHEETS INTO A STREAM OF OVERLAPPED SHEETS BACKGROUND OF THE INVENTION The present invention relates generally to a sheet handling apparatus, and more particularly to an apparatus for converting a stack of sheets into a stream of overlapped sheets.

There are circumstances where it is desirable and necessary to convert a stack of sheets into a stream of overlapped sheets. From Swiss Pat. No. 51 l,l75 it is known to provide an apparatus in which an operator deposits a stack of sheets on a conveyor, and thereupon converts this stack into a stream of partially overlapped sheets. This is done manually, in that the operator must exert manually a push against the sheets of the stack, so that the sheets slide apart in the longitudinal direction of the path in which they are being conveyed.

Aside from the fact that this prior-art apparatus requires the constant pressing of an operator, which of course is an expensive proposition, it has the drawback that an operator can hardly if ever uniformly distribute the sheets of the stack in such a manner that each sheet will substantially uniformly overlap a portion of the preceding sheet. There are, however, instances, where such precision is required.

SUMMARY OF THE INVENTION It is, therefore, a general object of the present invention to provide an apparatus for converting a stack of sheets into a stream of overlapped sheets.

More particularly, it is an object of the invention to provide such an apparatus which eliminates any manual operation, for converting the stack of sheets into a stream of overlapped sheets.

Another object of the invention is to provide such an apparatus which will represents savings in operational terms inasmuch as it does not require the constant presence of an operator.

In keeping with these objects and with others which will become apparent hereafter, one feature of the invention resides, in an apparatus for converting a stack of sheets into a stream of overlapped sheets, in a combination comprising first conveying means for conveying a stack of sheets which stand on edge, in a path. Second conveying means is provided at a level above the path. Pick-up means is provided for successively picking up the respectively leading sheets of the stack. Transfer means cooperates with the pick-up means for transferring each picked-up sheet to the second conveying means and depositing it thereon in partially overlapping relationship with a preceding sheet.

The apparatus according to the present invention eliminates the need for manual operations by an attendant and thus represents a saving in terms of labor expenses. Moreover, it permits the conversion of large stacks of sheets (for instance newspaper-sheets or the like) without having to first bundle them, and thus increases the speed of operation considerably over what is known from the prior art.

Moreover, the uniformity with which successive sheets overlap one another is significantly improved with the apparatus according to the present invention.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however,

both as to its construction and its method of operation, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a partially sectioned side view illustrating one embodiment of the invention;

FIG. 2 is a vertical section through FIG. 1;

FIG. 3 is a fragmentary vertical section illustrating a further embodiment of the invention;

FIG. 4 is a fragmentary view, illustrating a circuit used in the embodiment of FIG. 3; and

FIG. 5 is a diagrammatic side view illustrating a detail of the embodiment in FIGS. 3 and 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing the drawing now in detail, and referring to the embodiment illustrated in FIGS. 1 and 2, it will be seen that reference numeral 1 identifies a stack of sheets for instance newspaper sheets, book-pages, leaflets or the like. The stack I is located on an endless conveyor 2 so that the sheets stand on edge, as shown. The conveyor 2 utilizes, as illustrated in FIG. 2, two transversely spaced endless belts which are provided with abutments 3 against which the respective stack I rests. The direction in which each stack I is advanced is indicated by the arrow in FIG. I. The belts of the conveyor 2 are trained about rollers 5 mounted on a shaft 4, at the front end of the conveyor 2, and about similar rollers mounted on a similar shaft at the rear end of the conveyor 2 (not shown). The shaft 4 or the shaft at the rear end may be connected with the drive (not shown) to drive it in rotation. The rollers on the non-driven shaft may rotate freely about the shaft on which they are mounted. It is advantageous if the conveyor 2 is upwardly inclined in the direction of advancement of the stack 1 as shown in FIG. 1.

Located above, and extending transversely to the path in which the stack 1 is advanced there is provided a shaft 6, which is turnably journalled in two lateral supports 7 and 8. A pick-up unit 9 is suspended from the shaft 6 so that it can tilt about the same quite freely. The unit 9 has a pair of upper lugs 10 and a pair of center lugs 11, as well as a lower lug 12; these are all connected by means of shafts l3 and 14 extending in parallelism with the shaft 6 but being downwardly spaced therefrom. The upper ends of the pair of lugs 10 are connected to the shaft 6 so that they can pivot on it. The shaft 13 is turnably mounted at the lower ends of the lugs 10, and in turn the upper ends of the lugs 11 are pivoted on the shaft 13. The shaft 14 is turnably mounted on the lower ends of the lugs 11, and on this shaft the lug 12 is pivotally connected. At the lower free end of the lug 12 there is turnably mounted a further shaft 15. Three rollers 16 are mounted on the shaft 6 for rotation with but not relative to the same. A corresponding number of rollers I7 are provided on the shaft 13 to rotate with the same but not relative to the same. Two additional rollers 18 are mounted on the shaft 13, and a corresponding number of rollers 19 is mounted on the shaft 14, which in addition carries two polygonal (here hexagonal) rollers 20, with two similar polygonal rollers 21 provided on the shaft I5. Endless belts of material having a high-friction surface cooperate with the rollers. In particular, a belt 22 is trained about rollers 16 and 17, a belt 23 about the rollers 18 and 19, and a belt 24 about the rollers and 21. A further shaft 25 is turnably journalled in the supports 7 and 8, and carries rollers 26 about which a belt 27 of an upper conveyor is trained, the rollers at the opposite end of the belt 27 having been omitted as not essential for an understanding of the invention. The belt 27 is actually composed of three laterally adjacent parallel sections, as shown in FIG. 2.

Rollers 28 are also mounted on the shaft 25 intermediate the rollers 26, and two corresponding rollers 29 are provided on the shaft 6. Endless belts 30 having high friction surfaces are trained about the cooperating rollers 28 and 29. The belts 22, 23 and 24 are driven in the direction of the indicated arrows, by the belts 30.

Transfer and pressing means is provided which cooperates with the unit 9 and with the belts 27 and 30. It uses a plurality of endless belts 31, here five of them. The facing runs of the belts of the unit 9, as well as the belts 27 and 30, advance in one and the same direction and at identical rate of speed. The belts 31 define with the upper portion of the unit 9, a wedge-shaped inlet gap 32 for the sheets withdrawn from the stack 1. The belts 31 are trained about rollers 33, 34, 35, 36 and 37. Of these the rollers 33 are non-rotatably connected with a shaft 38 which is turnably journalled in the supports 7 and 8. The rollers 35 and 36 are respectively freely turnably mounted on shafts 39 and 40 which are fixedly mounted in the supports 7 and 8. Rollers 34 and 37 are turnably journalled on shafts 33 and 34 which are fixedly mounted on the arms 41 and 42 which are clamped against the shafts 39 and 40. The belts 31 can either be undriven or they can be driven by the same drive which drives the belts 27.

The drive for the belts 27 has not been illustrated, because it is conventional and can be provided in form of an electromotor or the like. When it is energized the belts 27 are advanced and at the same time, the belts 31 and the belts of the unit 9. When a stack of sheets is advanced in the direction of the arrow in FIG. 1, that is towards the right, it will come in contact with the unit 9, pivoting the same in counterclockwise direction to a slight extent, until it is in good frictional engagement with the leading sheet of the stack against which the unit presses under the influence of its own weight. Due to the friction between the unit 9 on the one hand, and the leading sheet of the stack 1 on the other hand, the sheet is engaged by the belts of the unit 9 and raised upwardly into the gap 32, where it moves between the belts 22 and 31, to be engaged by the same and transported onto the belts 27.

As soon as the abovementioned leading sheet has been lifted off the conveyor 2 by the distance b (see FIG. I) the lower end of the unit 9 will already be in contact with the next following sheet of the stack 1, which is now the new leading sheet. As a result of this engagement, the unit will now lift this new leading sheet upwardly in the same direction. It will be appreciated that this new leading sheet will then be deposited on the belts 27 and, since these also advance, the new leading sheet will partially overlap the sheet which was previously deposited on the belts 27.

The extent of the overlap can be varied by changin the distance b. The fact that the rollers 20 and 21 are polygonal produces a vibration which acts upon the end of the stack 1, that is adjacent the unit 9, and which facilitates the upward withdrawal of the respective leading sheets of the stack.

The advancement of the conveyor 2 towards the right in FIG. 1, is controlled by an on-off switch 45 having a sensor 46. The switch is mounted in the support 7, being adjustable in the direction of advancement of the conveyor 2, and the sensor 46 interrupts the power supply circuit of the non-illustrated drive motor, which drives the conveyor 2 when the sensor 46 is depressed as shown in FIG. 1. This takes place while there is proper frictional engagement between the unit 9 and the stack 1.

However, as soon as a few of the leading sheets of the stack 1 have been withdrawn from unit 9, the force acting upon the sensor 46 and deflecting it to the position shown in FIG. 1, will decrease and terminate, it being understood that the stack 1 is stationary at this time, so that its right-hand end tends to recede from the unit 9 as the latter picks up and removes successive ones of the leading sheets at the right-hand end. When this takes place and the sensor 46 is no longer deflected to the illustrated position, the sensor closes the power supply circuit for the motor, which now advances the conveyor 2 and causes the stack 1 to be pushed against the unit 9 again, as before. The advancement of the stack 1 towards the right in FIG. 1 continues until the sensor 46 is again lifted to the position shown in FIG. 1, and, interrupts the power supply circuit for the motor. The distance through which the sensor 46 must travel to complete and interrupt the power supply circuit is advantageously small, to insure that the righthand leading end of the stack 1 will be as much as possible in constant contact with the unit 9. A displacement of the switch 45 in the support 7 permits the position of the right-hand end of the stack 1 to be selected with reference to the unit 9, in accordance with the particular requirements of a given situation, for instance depending upon the type of sheets which make up the stack 1.

One or more air nozzles 47 are arranged beneath the right-hand end of the stack 1, and therefore of the conveyor 2, which receive air under pressure from a nonillustrated source and direct a stream or streams of air towards the unit 9, and therefore, against the several leading sheets at the right-hand end of the stack 1. This reduces the friction between these sheets and the nextfollowing ones, and further facilitates the withdrawal of the leading sheets by the unit 9.

A detector 48 of an on-off switch 49 is arranged below the upper run of the conveyor 2 and presses from below against sheets at the right-hand leading end of the stack 1. These sheets maintain the detector 48 in the somewhat downwardly deflected position which is shown in FIG. 1.

If, however, a stack has been withdrawn in its entirety, then there is no further downward force upon the detector 48 which can now move upwardly since it is of springy construction. The detector 48 remains in this position during the period of time which ellapses between the complete withdrawal of one stack 1 and the arrival the next stack, which is spaced from the preceding stack by a gap on the conveyor 2. In accordance ith the present invention the drive for the conveyor 2 incorporates not only an arrangement for driving the latter in slow motion under the influence of the sensor 46, but also an arrangement for driving it in fast highspeed motion (neither of these arrangements is shown because they are both known from the art). The detector 48 is connected with the drive, and in particular with the arrangement for driving the conveyor 2 at high speed motion. When it flexes upwardly on detecting the gap between two successive ones of the stacks I, it en ergizes the arrangement for high speed advancement of the conveyor 2 so that the time period required for the next following stack 1 to move into position in which its sheets can be withdrawn by the unit 9, is significantly reduced. Of course, when the next stack moves into position, it will deflect the detector 48 which in consequence will switch-off the high-speed drive arrangement of the conveyor 2.

It may be desired or even necessary to be able to control the advancement of the conveyor 2 in such a manner that it can be regulated continuously. If so, the embodiment of FIGS. 3 5 may be employed in the apparatus of FIGS. 1 and 2, in place of the switch 45.

FIG. 3 shows that in this case, the lugs are not pivoted on the shaft 6, but instead are fixedly connected with the same so that they cannot pivot relative to it. The shaft 6 itself is turnably journalled in the supports 7 and 8. Laterally adjacent the support 7, the shaft 6 carries a belt pulley 100 which turns with the shaft 6. A further belt pulley 101 is mounted on a shaft 105 with which it turns and a belt 102 connects the two pulleys 100 and 101 to transmit motion between them. The shaft 105 is operatively connected with a device 103 which in the particular illustrated embodiment is a potentiometer of the controlled direct current drive 104. The Rollers R for the belts 22, 30 are here freely rotatably journalled on shaft 6 by means of the bearings B shown in FIG. 3.

When the shaft 105 turns, the potentiometer 103 is operated, and the further the unit 9 (see FIG. 5) is deflected from its ideal operating position towards the left or towards the right, (see the angles a and a in FIG. 4), the more the drive 104 will be accelerated or retarded by the potentiometer 103. Depending upon the transmission ratio of the belt drive 100, 101 and 102, the angles a and a can be selected larger or smaller as desired.

The electrical circuit for the arrangement in FIGS. 3 to 5 is partially and diagrammatically shown in FIG. 4 and will be self-evident.

It is also possible, but not illustrated, that the polygonal rollers and 21 be replaced by circular rollers in the unit 9 if this is desired.

Another possibility in accordance with the present invention, which is also not illustrated, provides for the unit 9 to be provided only with the rollers 17 and 21, and to use only two belts, one of which connects the rollers 17 and 21, and the other of which connects the rollers 16 and 17. On the other hand, the unit 9 can of course be subdivided still further beyond that what is shown in FIG. 1.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in an apparatus for converting a stack of sheets into a stream of overlapped sheets, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

.Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention, and therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

1. In an apparatus for converting a stack of sheets into a stream of overlapped sheets, a combination comprising first conveying means for conveying a stack of sheets which stand on edge in a substantially horizontal path; second conveying means at a level above said path; pick-up means for successively picking up the respectively leading sheets of said stack, said pick-up means comprising a unit which is mounted for tilting movement about a shaft defining a substantially horizontal axis which extends across said path and includes endless rotatable pick-up belt means which is elongated in upright direction and has an upper portion located above said path, and a lower portion which is normally in contact with the respective leading sheet; and transfer means cooperating with said pick-up means for tranferring each picked-up sheet to said second conveying means and depositing it thereon in partially overlapping relationship with a preceding sheet.

2. A combination as defined in claim I, wherein said transfer means comprises an endless travelling presser belt having an elongated part one end of which is pressed against said upper portion of said pick-up belt means and defines therewith a wedge-shaped gap for entry of said sheets, and an other end of which is pressed against said second conveying means and from which said sheets are deposited onto the latter, said belt, belt means and second conveying means all travelling at the same rate of speed.

3. A combination as defined in claim 2, wherein said unit includes a plurality of additional shafts below the first-mentioned shaft and extending in axial parallelism with the same and with one another, and rollers mounted on the respective shafts, all of said shafts being rotatable and said rollers being fixed on said shafts; and wherein said pick-up belt means includes a plurality of endless pick-up belts each of which is trained about the rollers on two successive ones of said shafts.

4. A combination as defined in claim 3, wherein said shafts include a lowermost shaft; and wherein the rollers on said lowermost shaft are of polygonal outline.

5. A combination as defined in claim 4, wherein the rollers on the successive shaft above said lowermost shaft are also polygonal.

6. A combination as defined in claim 2; further comprising drive means for said first conveying means; and sensing means associated with said drive means and operative for sensing loss of contact between said lower portion and the stack which occurs after removal of several of said leading sheets, said sensing means activating said drive means in response to sensing of such loss of contact so that said first conveying means advances said stack in said path and against said lower portion, and deactivating said drive means in response to restoration of the contact.

7. A combination as defined in claim 2; and further comprising air nozzle means arranged below said first conveying means for directing a stream of air towards said unit.

8. A combination as defined in claim 2, wherein said unit tilts about said axis in response to contact with said stack; further comprising drive means for causing said first conveying means to convey said stack towards said unit; and analog-circuit means associated with said unit and said drive means for activating and deactivating the latter in response to the tilting of said unit.

9. ln an apparatus for converting a stack of sheets into a stream of overlapped sheets, a combination comprising first conveying means for conveying a stack of sheets which stand on edge, in a substantially horizontal path; second conveying means at a level above said path; pick-up means for successively picking up the respectively leading sheets of said stack, said pick-up means comprising a unit which is mounted for tilting movement about a shaft defining a substantially horizontal axis which extends across said path and includes endless rotatable pick-up belt means which is elongated in upright direction and has an upper portion located above said path, and a lower portion which is normally in contact with the respective leading sheet; transfer means cooperating with said pick-up means for transferring each picked-up sheet to said second conveying means and depositing it thereon in partially overlapping relationship with a preceding sheet, said transfer means comprising an endless travelling presser belt having an elongated part one end of which is pressed against said upper portion of said pick-up belt means and defines therewith a wedge-shaped gap for entry of said sheets, and another end of which is pressed against said second conveying means and from which said sheets are diposited onto the latter, said belt, belt means and second conveying means all travelling at the same rate of speed; drive means for selectively driving said first conveying means at a slow speed and at a fast speed; and detecting means associated with said drive means and operative for causing the same to drive said first conveying means at said fast speed in response to detection of a gap between two successive stacks on said first conveying means by said detecting means. 

1. In an apparatus for converting a stack of sheets into a stream of overlapped sheets, a combination comprising first conveying means for conveying a stack of sheets which stand on edge in a substantially horizontal path; second conveying means at a level above said path; pick-up means for successively picking up the respectively leading sheets of said stack, said pick-up means comprising a unit which is mounted for tilting movement about a shaft defining a substantially horizontal axis which extends across said path and includes endless rotatable pick-up belt means which is elongated in upright direction and has an upper portion located above said path, and a lower portion which is normally in contact with the respective leading sheet; and transfer means cooperating with said pick-up means for tranferring each picked-up sheet to said second conveying means and depositing it thereon in partially overlapping relationship with a preceding sheet.
 2. A combination as defined in claim 1, wherein said transfer means comprises an endless travelling presser belt having an elongated part one end of which is pressed against said upper portion of said pick-up belt means and defines therewith a wedge-shaped gap for entry of said sheets, and an other end of which is pressed against said second conveying means and from which said sheets are deposited onto the latter, said belt, belt means and second conveying means all travelling at the same rate of speed.
 3. A combination as defined in claim 2, wherein said unit includes a plurality of additional shafts below the first-mentioned shaft and extending in axial parallelism with the same and with one another, and rollers mounted on the respective shafts, all of said shafts being rotatable and said rollers being fixed on said shafts; and wherein said pick-up belt means includes a plurality of endless pick-up belts each of which is trained about the rollers on two successive ones of said shafts.
 4. A combination as defined in claim 3, wherein said shafts include a lowermost shaft; and wherein the rollers on said lowermost shaft are of polygonal outline.
 5. A combination as defined in claim 4, wherein the rollers on the successive shaft above said lowermost shaft are also polygonal.
 6. A combination as defined in claim 2; further comprising drive means for said first conveying means; and sensing means associated with said drive means and operative for sensing loss of contact between said lower portion and the stack which occurs after removal of several of said leading sheets, said sensing means activating said drive means in response to sensing of such loss of contact so that said first conveying means advances said stack in said path and against said lower portion, and deactivating said drive means in response to restoration of the contact.
 7. A combination as defined in claim 2; and further comprising air nozzle means arranged below said first conveying means for directing a stream of air towards said unit.
 8. A combination as defined in claim 2, wherein said unit tilts about said axis in response to contact with said stack; further comprising drive means for causing said first conveying means to convey said stack towards said unit; and analog-circuit means associated with said unit and said drive means for activating and deactivating the latter in response to the tilting of said unit.
 9. In an apparatus for converting a stack of sheets into a stream of overlapped sheets, a combination comprising first conveying means for conveying a stack of sheets which stand on edge, in a substantially horizontal path; second conveying means at a level above said path; pick-up means for successively picking up the respectively leading sheets of said stack, said pick-up means comprising a unit which is mounted for tilting movement about a shaft defining a substantially horizontal axis which extends across said path and includes endless rotatable pick-up belt means which is elongated in upright direction and has an upper portion located above said path, and a lower portion which is normally in contact with the respective leading sheet; transfer means cooperating with said pick-up means for transferring each picked-up sheet to said second conveying means and depositing it thereon in partially overlapping relationship with a preceding sheet, said transfer means comprising an endless travelling presser belt having an elongated part one end of which is pressed against said upper portion of said pick-up belt means and defines therewith a wedge-shaped gap for entry of said sheets, and another end of which is pressed against said second conveying means and from which said sheets are diposited onto the latter, said belt, belt means and second conveying means all travelling at the same rate of speed; drive means for selectively driving said first conveying means at a slow speed and at a fast speed; and detecting means associated with said drive means and operative for causing the same to drivE said first conveying means at said fast speed in response to detection of a gap between two successive stacks on said first conveying means by said detecting means. 